This is a list of selected September 23 anniversaries that appear in the "On this day" section of the Main Page. To suggest a new item, in most cases, you can be bold and edit this page. Please read the selected anniversaries guidelines before making your edit. However, if your addition might be controversial or on a day that is or will soon be on the Main Page, please post your suggestion on the talk page instead.
Please note that the events listed on the Main Page are chosen based more on relative article quality and to maintain a mix of topics, not based solely on how important or significant their subjects are. Only four to five events are posted at a time and thus not everything that is "most important and significant" can be listed. In addition, an event is generally not posted this year if it is also the subject of the scheduled featured article, featured listorpicture of the day.
To report an error when this appears on the Main Page, see Main Page errors. Please remember that this list defers to the supporting articles, so it is best to achieve consensus and make any necessary changes there first.
Use only ONE image at a time
| Blurb | Reason |
|---|---|
| National DayinSaudi Arabia (1932) | both "National Day" article and the country itself are orange tagged |
| 1123 – Pope Callixtus II and Holy Roman Emperor Henry V agreed to the Concordat of Worms to put an end to the Investiture Controversy. | needs more footnotes |
| 1459 – Yorkist forces led by Richard Neville defeated Lancastrian troops at the Battle of Blore HeathinStaffordshire, England, a major battle of the Wars of the Roses. | refimprove section |
| 1779 – American Revolutionary War: John Paul Jones led a Franco-American squadron to victory in the Battle of Flamborough Head, one of the most celebrated naval actions of the war. | rewrite, primary |
| 1821 – Greek War of Independence: Greek rebels captured Tripolitsa after a five-month siege and began a massacre of Muslim and Jewish residents. | needs more footnotes (9 {cn} tags) |
| 1845 – American bookseller Alexander Cartwright founded the New York Knickerbockers, one of the first organized baseball teams. | refimprove |
| 1846 – Using mathematical predictions by French mathematician Urbain Le Verrier, German astronomer Johann Gottfried Galle became the first person to observe Neptune and recognise it as a hitherto unknown planet. | lots of CN tags (7) |
| 1868 – Ramón Emeterio Betances led the Grito de Lares, a revolt against Spanish ruleinPuerto Rico. | needs more footnotes |
| 1899 – Philippine–American War: The American Asiatic Squadron destroyed a Filipino artillery batteryinOlongapo. | one source |
| 1932 – The Kingdom of Hejaz and Nejd merged with Al-Hasa and Qatif to form the Kingdom of Saudi Arabia, with Ibn Saud as the first monarch and Riyadh as the capital city. | refimprove |
| 1983 – A bomb placed by the Abu Nidal organisation destroyed Gulf Air Flight 771, flying from Karachi, Pakistan, to Abu Dhabi, UAE, killing all 112 people aboard. | expansion |
| 2002 – The first version of the web browser Firefox was released by the Mozilla Organization. | lots of citations needed (16) |
| Francesco Barberini |b|1597| | lots of citations needed (7) |
| El Santo |b|1917 | refimprove section |
| Bruce Springsteen |b|1949 | refimprove |
September 23: Celebrate Bisexuality Day
